This invention relates generally to improvements in lasers. More specifically, it relates to improvements in pulsed gas lasers.
Intense lasing action in a gas such as nitrogen requires the production of a high power, high voltage pulse of electrical energy, and the delivery of this energy into a well confined volume of gas in order to produce an intense discharge in the gas. If the quantum mechanical conditions are favorable then the energetic electrons in the discharge can initiate processes that result in the selective over-population of particular excited states of the substance (so-called population inversion) producing lasing action or superradiant optical de-excitation of the excited states. Favorable conditions for lasing action require the volume of excited gas, which is to say the discharge region, be much longer in one of its dimensions as is a slender cylinder or long rectangular bar. If the above conditions are fulfilled, and the discharge is of sufficient intensity and uniformity, then intense lasing action may be expected as in the case for molecular nitrogen where lasing takes place predominately at wavelengths near 337.1 nanometers. A mirror at one end of the discharge region and a partially reflecting window at the other end will usually enhance the directionality and intensity of the laser beam. All of the above are generally well known characteristics of pulsed high power gas lasers where the required population inversion is obtained by producing an intense discharge in the gas.
However the design and construction of pulsed high power gas discharge lasers which are at the same time low in cost and of high reliability has not generally been achieved for the particular situation where the electrical voltages required are of the order of 10 kilovolts or greater and with the additional requirement that this electrical energy must be delivered into the gas in very short times that may be of the order of several nonoseconds. (One nanosecond = 10.sup.-9 sec.)
Therefore it is an object of this invention to provide a novel lasing apparatus which is both economical and reliable.
It is another object of this invention to provide novel lasing apparatus in which economical construction is achieved by utilizing various circuit elements to perform dual electrical and mechanical functions.
A particular element which may have a relatively short life when switching the high voltages required for laser operation is the switch controlling the energy flow to the laser tube. Thus such devices may have their lives shortened because concentrated high voltage arcs or sparks cause local heating on a solid surface. On succeeding operations of the switch the hot spot tends to promote the occurrence of the arc or spark at the same location resulting in pitting of the surface and consequently reduced life.
Therefore it is another object of this invention to provide an improved laser having a novel high voltage switch capable of a very large number of operations.
Another object of this invention is to provide a novel laser apparatus wherein a single switch device can be used to switch one or more than one energy storage circuits.
As stated above, it is important for lasing action that the discharge in a laser tube be of sufficient intensity and uniformity.
Consequently it is a further object of this invention to prove a novel laser tube constructed to provide a highly concentrated and uniform electrical discharge.
In addition it is an object of this invention to provide a novel laser having unique gas supply means permitting a uniform distribution of the gas over the length of the tube.